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novas 3.1.1.3

What is NOVAS?

NOVAS is an integrated package of functions for computing various
commonly needed quantities in positional astronomy. The package can
supply, in one or two function calls, the instantaneous coordinates of
any star or solar system body in a variety of coordinate systems. At a
lower level, NOVAS also provides astrometric utility transformations,
such as those for precession, nutation, aberration, parallax, and
gravitational deflection of light. The computations are accurate to
better than one milliarcsecond. The NOVAS library is an easy-to-use
facility that can be incorporated into data reduction programs,
telescope control systems, and simulations. The U.S. parts of
The Astronomical Almanac are prepared using NOVAS.

This Python package includes both the NOVAS library and the Python
wrapper that are available from the NOVAS home page at the United
States Naval Observatory. This version includes a few bug fixes and
packaging adjustments that are not in the most recent June 2011
release of the software from the Naval Observatory itself. You can
find these changes described at the bottom of this page in the
Changelog, and you can also review them yourself at the project
repository on GitHub.

This package has been uploaded to the Python Package Index by Brandon
Rhodes <brandon@rhodesmill.org>. Please contact me, and not the busy
folks at the Naval Observatory, about any problems you encounter when
trying to install it — any problems with how it has been packaged are
my fault, not theirs! For questions about how to use the library, you
can also ask for help on Stack Overflow, where I watch for questions
that involve Python and astronomy.

Installation

Like other packages listed here on the Python Package Index, this
package can be installed with the pip command. You will need to
install both the library itself as well as a high-accuracy ephemeris
data set, with the DE405 ephemeris being the current default:

$ pip install novas
$ pip install novas_de405

Note that the second command may take several minutes to run, depending
on your Internet connection, because the JPL ephemeris that it has to
download is 55 MB in size!

If you are managing a Python project that has a setup.py or a
requirements.txt file, then instead of running these pip
commands manually you can simply list these two package names alongside
the other packages that you depend on, and let them be installed as part
of your normal project install.

Sanity check: running the tests

Once the package is installed, you can run its tests with the new
test-discovery feature built-in to Python 2.7. If the tests pass to
extremely high accuracy, then the result should be:

Changelog

Version 3.1.1.3 — 2015 January 23

Version 3.1.1.2 — 2013 July 31

The top-level __init__.py now attempts to load the NOVAS C library
from several different filenames under Python 3, instead of only
trying filenames with an ABI identifier. (On my Ubuntu 13.04 laptop,
Python 3.3 is not in fact including such an identifier, which was
causing an ImportError: cannot import name novaslib failure.)

Version 3.1.1.1 — 2013 March 2

Further fixes have been provided by users, so I am making this interim
release while the official version still sits at 3.1.

Leo Singer fixed the wrappers for cal_date() and limb_angle()
so these two NOVAS functions can now be used from Python code.

The setup.py now specifies the encoding for this readme, so the
package can install on systems where UTF-8 is not the default.

Version 3.1.1 — 2012 November 25

The Naval Observatory has not released a new version of NOVAS since
June 2011, but reports and requests from users convinced me to make
several small fixes to the code and make an interim release here on
the Python Package Index:

The library is now Python 3 compatible!

Python code can now access the ephem_close() routine inside the
eph_manager module.

Bugfix: the eph_manager.state() function was always raising an
exception if invoked.

Version 3.1 — 2012 September 19

Initial release of the library on the Python Package Index.

License and Citation

This software was produced by the United States Naval Observatory at the
expense of United States taxpayers, and is therefore not suseptible to
copyright, because a copyright would place taxpayer property under
private ownership. Since it is not copyrighted, it cannot be licensed;
it is simply free.

The authors of NOVAS ask that if you use their software in your work,
that you let them know at help@aa.usno.navy.mil since a record of who is
using their software helps them justify the excellent work that they are
doing by making the software available to the public.